Coal cutter with vibratory drive



Dec. 31, 1968 H. ULUSAL 3,419,313

COAL CUTTER WITH VIBRATORY DRIVE Filed May 5, 1967 WWW mvg my 20 23 4 /4 H T] P 5 FIG. 3 9

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INVENTOR HL JSEYIN ULUSAL, DECEASED BY NURIYE ULUSAL.LEGAL REPRESENTATIVE BY n United States Patent C F 3,419,313 COAL CUTTER WITH VIBRATORY DRIVE Hiiseyin Ulusal, deceased, late of Altlunen, Westphalia, Germany, by Nuriye Ulusal, heir, Altlunen, Westphalia, Germany, assignor to Gewerkschaft Eisenhiitte Westfalia, Wethmar, near Lunen, Westphalia, Germany, a corporation of Germany Filed May 5, 1967, Ser. No. 636,554

Claims priority, application Germany, May 12, 1966,

9 Claims. (Cl. 29934) ABSTRACT OF THE DISCLOSURE Vibration cutter including cutter body having cutting tools at the longitudinal ends thereof for engaging extractively a mine face in a longitudinal direction along which such body is conducted, and a vibration generator on the cutter body including two unbalanced flywheels arranged, e.g. via an electric motor drive, for synchronous rotation in opposite directions on horizontally disposed parallel shafts extending substantially transversely of such longitudinal direction and mounted rotatably on the cutter body, one or both flywheels being limitedly freely rotatable with respect to the corresponding shaft therefor in the direction of rotation, whereby during flywheel rotation vibrations are produced in the cutter body predominantly in the longitudinal cutting direction and in the direction opposite thereto but at an angle, e.g. acute angle, to the mine floor.

The present invention relates to a mineral cutter with a vibratory drive, and more particularly to such a cutter having two unbalanced flywheels arranged for synchronous rotation in opposite directions on horizontal parallel shafts, with at least one of the flywheels being limitedly freely rotatable with respect to its shaft to achieve vibrations of the cutter parallel to the mine face yet at an acute angle to the mine floor.

It is known that by means of counter-rotating unbalanced flywheels it is possible to generate directional vibrations. In order that a coal cutter provided with such a vibrational drive should itself be able to move, the direction of action of the vibrations must not be exclusively confined to a horizontal plane bust must rather be directed between the horizontal and vertical. Since in the case of a coal cutter what matters is to generate as high an impact energy in the horizontal direction as possible in order to detach the coal from the mining seam, the direction of vibration is so adjusted that the horizontal component is as large as possible. The effect of this is then as large an impact energy against the coal as possible. At the same time it is arranged that the vertical component of the vibratory drive is still just sufliciently large that the pressure against the floor is not excessive and that also no excessive dust is generated. This is because the cutter does not necessarily have to lift completely off the floor. It suflices if it is sufliciently relieved of load to execute a sort of hopping motion in conjunction with the horizontal component. The vertical component must be of such magnitude that, with the weight of the cutter added to it, it just suflices to absorb the recoil produced when the impact energy is transferred to the coal. By arranging the shafts carrying the flywheels one behind the other varying moments act on the cutter body. The result of this is that with each revolution of the flywheels the cutter body attempts once to lift its front end and once to lift its rear end from the floor. This process produces a slight up and down vibration at the cutter tips, i.e. tipping and nodding motions, which again assists the detachment of coal from the seam.

3,419,313 Patented Dec. 31, 1968 It is an object of the present invention to overcome prior art disadvantages and to provide a mineral cutter with a vibratory drive including two unbalanced flywheels arranged for synchronous rotation in opposite directions on horizontal parallel shafts, with at least one of the flywheels being limitedly freely rotatable with respect to its shaft to achieve vibrations of the cutter parallel to the mine face yet at an angle, especially an acute angle, to the mine floor.

Other and further objects of the present invention will become apparent from a study of the within specification and accompanying drawing, in which:

FIG. 1 schematically shows a side view of the cutter, viewed from the coal seam;

FIG. 2 schematically shows a horizontal section approximately along line II-II of FIG. 1;

FIG. 3 schematically shOWS the position of the flywheels when the cutter moves to the right indicating the resultant force vector diagram appropriate thereto; and

FIG. 4 schematically shows the position of the flywheels when the cutter moves to the left indicating the resultant force vector diagram appropriate thereto.

It has now been found, in accordance with the present invention, that a mineral cutter such as a coal cutter may now be provided with a built-in vibration generator in order to cause the cutter as a whole, or its tool carrier only, to execute vibrations at an acute angle to the floor and parallel to the coal seam. The drive for the vibration generator may be supplied by an endless chain whose length passes through the entire working area or mine and whose drum drives are located in the galleries. The cutter may however additionally or alternatively be provided with an independent electric motor or hydraulic motor to drive the vibration generator. When so driven, the vibrations are, in accordance with the present invention as appreciated from the drawing, caused by two flywheels rotating in opposite directions and having an eccentric centre of gravity.

In order to ensure, even with a counter-rotating movement, that the resultant of the recoil forces of both flywheels should run upwards at an angle, at least one of the flywheels is, according to the invention, thus capable of rotating freely about its shaft between stops. The play, i.e. the freedom of rotational movement which is defined by the stops, is of such magnitude that on changing over the direction of rotation the position of the flywheels relative to one another changes in such a way that even on changing the direction of rotation a vibration which now runs upwards at an angle in the new direction is produced.

Instead of only arranging one of the flywheels so as to have a limited freedom of rotation about its shaft, both flywheels may have limited freedom of rotation about their shafts. Since the two shafts in any case counterrotate, this results in every case in a phase displacement between the two unbalanced flywheels as is necessary in accordance with the present invention.

In an advantageous further development of the instant invention, the motor provided with a horizontal axis of rotation may be arranged between the shafts carrying the flywheels, e.g. transverse to the longitudinal working direction. For this, the axis of the motor can be coupled to one shaft carrying a flywheel by means of a chain and to the other shaft carrying a flywheel by means of a gear drive which reverses the direction of rotation. This embodiment is firstly very stable and appropriate and second- 1y produces the above-mentioned tipping and nodding motions of the cutter which assist the winning of the mineral.

The drive energy may however alternatively be transmitted to the shafts carrying the unbalanced flywheels in any other desired manner, provided it is arranged that the shafts always counter-rotate and run at the same speed of revolution.

It is advantageous to mount elastic elements below the cutter body, which exhibit increased friction relative to the floor. This largely absorbs the recoil of the cutter so that the motor output is predominantly uilized usefully for detaching the coal from the seam.

According to a further feature of the present invention, easy accessibility of the various moving parts or devices and a resistant construction of the coal cutter results from bearing the drive and the shafts carrying the flywheels in a cutter body constructed in the manner of a frame; the openings of such a frame cutter body can be closed off by removable cover plates.

One illustrative and non-limiting embodiment in accordanw with the instant invention is described below wih reference to the accompanying drawing.

Referring to the drawing and especially FIGS. 1 and 2, the cutter body 1 is constructed as a frame which is connected with the chisel carriers 2 and 20, arranged for operatively engaging the mine face 33 (see FIG. 2), to give a robust, durable and resistant unit. The cutter body 1 is tightly closed at its rear face and front face by removable rear and front cover plates 3 and 4, respectively. Nevertheless the constructional parts arranged within cutter body 1 are easily accessible for servicing and, where necessary, for replacement. A top cover plate 5 closes cutter body 1 at its top face.

The stator 6 of an electric motor (6, 7, 8) or other suitable drive means is arranged in the frame-shaped cutter body 1 with its axis extending transversely of the longitudinal axis of cutter body 1. The rotor 7 with the shaft 8 is rotatable within stator 6, i.e. in bearings 9 and 10 of the interior housing of cutter body 1. While the bearing 9 is directly supported in the cutter body 1, bearing 10 is arranged in an opening of the detachable intermediate cover plate 11 mounted in the interior housing of cutter body 1 under rear plate 3. Having these different bearing arrangements facilitates assembly, as the artisan will appreciate.

The shaft 8 carries a sprocket 12 at one end, external of intermediate plate 11, and a gear wheel 13 at the other end, beneath front plate 4. The drive energy is transmitted from the sprocket 12 as well as from the gear wheel 13 to the corresponding shafts 17 and 16 carrying the unbalanced flywheels 15 and 14, respectively. The shaft 16 is rotatable in the bearings 18 and 19 and the shaft 17 is similarly rotatable in the bearings 18 and 19. A gear wheel 20 is fixed to one end of the shaft 16 while the other shaft 17 carrying the flywheel 15 is provided with a sprocket 21 at the correspondingly opposite end. The sprockets 12 and 21 for driving shaft 17 and flywheel 15 are connected together by chain 22 (shown schematically in FIG. 1). The intermediate gear wheels 23 and 24 are introduced between the gear wheels 13 and 20 suitably mounted in the interior housing of cutter body 1 to provide a corresponding gear train for driving shaft 16 and flywheel 14. These gear wheels and sprockets are of such size as to ensure synchronous rotation, i.e. the same speed of rotation, of the corresponding shafts 16 and 17, though the shafts admittedly counter-rotate as has already been explained, whereby to achieve the purposes of the present invention.

Like the shafts 16 and 17, the flywheels 14 and 15 also rotate at the same speed of revolution when the motor (6, 7, 8) is running, but in the opposite direction of rotation as will be understood from the foregoing. If the flywheels 14 and 15 move to the left, as shown in FIGS. 1 and 2, then the cutter body 1 executes a vibratory movement towards the right. This results from the fact that the shafts 16 and 17 on which the flywheels 14 and 15 are mounted, rest against the cutter body 1 and transmit their resultant forces thereto. Conversely, the cutter body 1 executes a vibratory movement towards the 4 left if the flywheels 14 and 15 are moved to the right. In this way the cutter body 1 is caused to oscillate in a longitudinal direction.

In order to achieve a forward movement of the cutter body 1 in the particular direction of cutting it is necessary to adjust the direction of action of the forces generated by the flywheels so that such direction is upwards at an angle. The vibrations of the cutter body which are then produced by the recoil forces are directed downwards at an angle. At the same time the vertical vibrational component is absorbed by elastic members 25 arranged on the underside of the cutter body 1 generally in resting contact with the mine floor 32 (see FIG. 1). The elastic members 25, which may for example consist of rubber or substances with rubber-like properties are so chosen as to increase the friction between the cutter body 1 and the fioor 32. As a result the recoil of the cutter body 1 is largely transmitted to the floor via the elastic members 25, yet with the greatest part of the energy transmitted to the cutter body 1 being usefully utilized for detaching coal from the seam or mine face 33. Since the cutter body 1 however is only pressed against the floor with in creased pressure if it swings backwards, it will, on swinging in the opposite direction, move upwards. The cutter body thus executes a sort of hopping motion.

FIGURES 1 and 2 additionally show in dot and dash line a traction cable such as a drag chain 26. By means of this drag chain 26 the cutter body can be pulled forward in one or other longitudinal directions along mine face 33 utilizing one of the drives 27 or 28 or both in unison. The chain 26 is primarily provided for emergencies, in order to be able to withdraw the cutter body rapidly from the working area, say for repairs which may become necessary or for other pertinent reasons. Where appropriate, the advance of the cutter body 1 may however also be assisted by the drag chain 26 during the loosening operation by which mineral such as coal is chipped away from mine face 33. The drives 27 and 28 thus only have to be constructed for relatively low power output.

Power for electric motor (6, 7, 8) may be provided in the conventional manner by electric cable means extending along the mine face out of the way of the mining operation. Appropriate guide means therefor may also be used such as the pulley guide arrangement shown in US. Patent 3,113,763 to Wendt.

In order to succeed in having the cutter body working equally favorably in both directions of movement without having to carry out special readjustments of the vibratory drive upon each change in operative direction, advantageously only the flywheel 14 is arranged in a fixed manner on the shaft 16, by means of a key 29, as may be seen particularly from FIGS. 3 and 4. On the other hand, the flywheel 15 can be rotated to a limited extent about its shaft 17, in a circumferential direction. This is achieved by providing the flywheel 15 with a broad groove or sector slot 30 in the circumferential direction, in conjunction with a striker or key stop 31 which is significantly narrower than the groove 30 and which is firmly fixed to the shaft 17. If the drive motor (6, 7, 8) rotates in a clockwise direction the shaft 17 is also rotated in a clockwise direction by means of the chain 22. The striker 31 thereupon rests against the front end of the groove 30 and carries the flywheel 15 with it (see FIG. 4). If however the direction of rotation of the drivemotor is changed, the position of the flywheel 15 relative to the shaft 17 also changes since now the striker 31 comes into contact with the opposite end of the groove 30 (see FIG. 3).

Thus with the motor running there is always a phase displacement between the two unbalanced flywheels 14 and 15. The result of this is that the vibrations of the cutter body which are generated do not take place exactly horizontally in the plane defined by the two shafts 16 and 17 Rather, the cutter body vibrates, as a result of the above-mentioned phase displacement, in the desired manner in a direction which is at an acute angle to the floor in such a way that whenever it swings backwards it impinges against the floor with increased pressure. The situation is different when swinging in the opposite direction, that is to say when swinging against the coal seam. It is above all important that when changing the direction of rotation of the drive i.e. when the two unbalanced flywheels 14 and 15 are also driven in correspondingly changed opposite directions, the directions in which the cutter body swings in the new opposite direction should also form an acute angle with the floor so that no additional change-overs or adjustments are necessary. The change-over of the rotational drive alone suflices to change the direction of operation of the cutter body so that it will continue to move in the given opposite direction.

If for example the line of action of the recoil forces should be inclined at to the horizontal and if this inclination of the line of action should be equally great in both directions of movement, so that the cutter body works uniformly in both directions, then the flywheel must be rotatable via groove 30 and striker 31 by about relative to the shaft which carries it. The forces arising at the cutter body with the two possible directions of travel are represented by vectors in FIGURES 3 and 4. In these figures, the horizontal component is designated P the vertical component is designated P and the resultant of forces is designated P The symbols S and S indicate the respective centers of gravity of flywheels 14 and 15 (see FIGS. 3 and 4).

Striker 31 may be provided with a tangential plug 31' or other adjustment means to change the range of play or degree of freedom of rotational movement between striker 31 and groove as shown schematically in FIG. 3.

Advantageously, therefore, in accordance with the present invention, a vibration cutter adapted to be conducted longitudinally back and forth along a mine floor adjacent a mine face for extracting mineral such as coal from such mine face may now be provided, which comprises longitudinal cutter body means having cutting tool means mounted at each longitudinal end thereof for engaging extractively such mine face in the appropriate longitudinal direction of movement thereof, and vibration generator means disposed operatively on said cutter body means including two unbalanced flywheels arranged for synchronous rotation in opposite directions on horizontally disposed parallel shafts extending substantially transversely of such longitudinal direction and mounted rotatably on said cutter body means, at least one of said flywheels being arranged on the corresponding shaft therefor with a limited degree of freedom of rotational movement in the direction of rotation, whereby upon rotation of said flywheels synchronously in opposite directions vibrations are produced in the cutter body means which are predominantly in the appropriate longitudinal cutting direction and in the direction opposite thereto but at an acute angle to the mine floor.

Preferably, as noted above, adjustment means are provided for adjusting the degree of freedom of rotational movement of said at least One of said flywheels on the corresponding shaft therefor.

Drive means are provided suitably on the cutter body means having a horizontal drive shaft arranged between the flywheel shafts which is operatively coupled at one end thereof to one of said flywheel shafts by means of a chain drive linkage and which is operatively coupled at the other end thereof to the other of said flywheel shafts by means of a gear drive linkage which reverses the direction of rotation of said other flywheel shaft with respect to the direction of rotation of said drive shaft and said one flywheel shaft. In particular, the cutter body means may be in the form of a frame enclosed longitudinally by removable cover plates serving as appropriate longitudinal outer walls thereof, and the drive shaft and flywheel shafts may be mounted rotatably in such frame interiorly of the cover plates. Also, the drive means may take the form of an electric or hydraulic motor or other mechanical means providing drive energy for rotating the drive shaft.

If desired, for important efficiency of operation, elastic friction elements, such as those composed of rubber material, may be secured to the underside of said cutter body means, whereby during operation the friction developed between the cutter body means and the mine floor is increased.

Moreover, the degree of freedom of rotational movement of one or both of the flywheels ma be provided by means of a sector slot defined in the corresponding flywheel and a coacting stationary key stop defined on the adjacent periphery of the shaft on which such flywheel is arranged, with said key stop extending radially outwardly into said slot for corresponding abutment with the ends of said slot. Such slot may be defined by a sector angle of about 20 degrees.

What is claimed is:

1. Vibration cutter adapted to be conducted longitudinally back and forth along a mine floor adjacent a mine face for extracting mineral such as coal from such mine face, which comprises longitudinal cutter body means having cutting tool means mounted at each longitudinal end thereof for engaging extractively such mine face in the appropriate longitudinal direction of movement thereof, and vibration generator means disposed operatively on said cutter body means including two unbalanced flywheels arranged for synchronous rotation in opposite directions on horizontally disposed parallel shafts extending substantially transversely of such longitudinal direction and mounted rotatably on said cutter body means, at least one of said flywheels being arranged on the corresponding shaft therefor with a limited degree of freedom of rotational movement in the direction of rotation, whereby upon rotation of said flywheels synchronously in opposite directions vibrations are produced in the cutter body means which are predominantly in the appropriate longitudinal cutting direction and in the direction opposite thereto but at an acute angle to the mine floor.

2. Cutter according to claim 1 wherein adjustment means are provided for adjusting the degree of freedom of rotational movement of said at least one of said flywheels on the corresponding shaft therefor.

3. Cutter according to claim 1 wherein drive means are provided on said cutter body means having a horizontal drive shaft arranged between the flywheel shafts which is operatively coupled at one end thereof to one of said flywheel shafts by means of a chain drive linkage and which is operatively coupled at the other end thereof to the other of said flywheel shafts by means of a gear drive linkage which reverses the direction of rotation of said other flywheel shaft with respect to the direction of rotation of said drive shaft and said one flywheel shaft.

4. Cutter according to claim 3 wherein said cutter body means is in the form of a frame enclosed longitudinally by removable cover plates serving as appropriate longitudinal outer walls thereof and wherein said drive shaft and said flywheel shafts are mounted rotatably in said frame interiorly of said cover plates.

5. Cutter according to claim 4 wherein said drive means includes an electric motor.

6. Cutter according to claim 1 wherein elastic friction elements are secured to the underside of said cutter body means, whereby during operation the friction developed between the cutter body means and the mine floor is increased.

7. Cutter according to claim 6 wherein said elastic friction elements are composed of rubber material.

8. Cutter according to claim 1 wherein the degree of freedom of rotational movement of said at least one of said flywheels is provided by a sector slot defined in the corresponding flywheel and a coacting stationary key stop defined on the adjacent periphery of the shaft on which such flywheel is arranged, with said key stop extending radially outwardly into said slot for corresponding abutment with the ends of said slot.

9. Cutter according to claim 7 wherein said slot is defined by a sector angle of about 20 degrees.

3,097,537 7/1963 Peterson 7461 8 3,150,724 9/1964 Oelkers 173-49 3,151,912 10/1964 Herrmann 29934 FOREIGN PATENTS 1,155,408 10/1963 Germany.

ERNEST R. PURSER, Primary Examiner. 

